add scaffolding for splitting of vectors.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44722 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/SelectionDAG/LegalizeTypes.cpp

@@ -68,8 +68,8 @@ void DAGTypeLegalizer::run() {
           ExpandResult(N, i);
         else if (MVT::getVectorNumElements(ResultVT) == 1)
           ScalarizeResult(N, i);     // Scalarize the single-element vector.
-        else         // Split the vector in half.
-          assert(0 && "Vector splitting not implemented");
+        else
+          SplitResult(N, i);         // Split the vector in half.
         goto NodeDone;
       } else {
         assert(Action == Legal && "Unknown action!");
@@ -96,8 +96,7 @@ void DAGTypeLegalizer::run() {
           // Scalarize the single-element vector.
           NeedsRevisit = ScalarizeOperand(N, i);
         } else {
-          // Split the vector in half.
-          assert(0 && "Vector splitting not implemented");
+          NeedsRevisit = SplitOperand(N, i); // Split the vector in half.
         }
         break;
       } else {

lib/CodeGen/SelectionDAG/LegalizeTypes.h

@@ -260,6 +260,19 @@ private:
   bool ScalarizeOperand(SDNode *N, unsigned OpNo);
   SDOperand ScalarizeOp_EXTRACT_VECTOR_ELT(SDNode *N, unsigned OpNo);
 
+  //===--------------------------------------------------------------------===//
+  // Vector Splitting Support: LegalizeTypesSplit.cpp
+  //===--------------------------------------------------------------------===//
+  
+  void GetSplitOp(SDOperand Op, SDOperand &Lo, SDOperand &Hi);
+  void SetSplitOp(SDOperand Op, SDOperand Lo, SDOperand Hi);
+  
+  // Result Vector Splitting: <128 x ty> -> 2 x <64 x ty>.
+  void SplitResult(SDNode *N, unsigned OpNo);
+  
+  // Operand Vector Scalarization: <128 x ty> -> 2 x <64 x ty>.
+  bool SplitOperand(SDNode *N, unsigned OpNo);
+  
 };
 
 } // end namespace llvm.

lib/CodeGen/SelectionDAG/LegalizeTypesSplit.cpp

@@ -0,0 +1,122 @@
+//===-- LegalizeTypesSplit.cpp - Vector Splitting for LegalizeTypes -------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by Chris Lattner and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements vector splitting support for LegalizeTypes.  Vector
+// splitting is the act of changing a computation in an invalid vector type to
+// be a computation in multiple vectors of a smaller type.  For example,
+// implementing <128 x f32> operations in terms of two <64 x f32> operations.
+//
+//===----------------------------------------------------------------------===//
+
+#include "LegalizeTypes.h"
+using namespace llvm;
+
+//===----------------------------------------------------------------------===//
+//  Result Vector Splitting
+//===----------------------------------------------------------------------===//
+
+/// SplitResult - This method is called when the specified result of the
+/// specified node is found to need vector splitting.  At this point, the node
+/// may also have invalid operands or may have other results that need
+/// legalization, we just know that (at least) one result needs vector
+/// splitting.
+void DAGTypeLegalizer::SplitResult(SDNode *N, unsigned ResNo) {
+  DEBUG(cerr << "Expand node result: "; N->dump(&DAG); cerr << "\n");
+  SDOperand Lo, Hi;
+  Lo = Hi = SDOperand();
+  
+#if 0
+  // See if the target wants to custom expand this node.
+  if (TLI.getOperationAction(N->getOpcode(), N->getValueType(0)) == 
+      TargetLowering::Custom) {
+    // If the target wants to, allow it to lower this itself.
+    if (SDNode *P = TLI.ExpandOperationResult(N, DAG)) {
+      // Everything that once used N now uses P.  We are guaranteed that the
+      // result value types of N and the result value types of P match.
+      ReplaceNodeWith(N, P);
+      return;
+    }
+  }
+#endif
+  
+  switch (N->getOpcode()) {
+  default:
+#ifndef NDEBUG
+    cerr << "SplitResult #" << ResNo << ": ";
+    N->dump(&DAG); cerr << "\n";
+#endif
+    assert(0 && "Do not know how to split the result of this operator!");
+    abort();
+    
+#if 0
+  case ISD::UNDEF:       SplitResult_UNDEF(N, Lo, Hi); break;
+#endif
+  }
+  
+  // If Lo/Hi is null, the sub-method took care of registering results etc.
+  if (Lo.Val)
+    SetSplitOp(SDOperand(N, ResNo), Lo, Hi);
+}
+
+
+//===----------------------------------------------------------------------===//
+//  Operand Vector Splitting
+//===----------------------------------------------------------------------===//
+
+/// SplitOperand - This method is called when the specified operand of the
+/// specified node is found to need vector splitting.  At this point, all of the
+/// result types of the node are known to be legal, but other operands of the
+/// node may need legalization as well as the specified one.
+bool DAGTypeLegalizer::SplitOperand(SDNode *N, unsigned OpNo) {
+  DEBUG(cerr << "Split node operand: "; N->dump(&DAG); cerr << "\n");
+  SDOperand Res(0, 0);
+  
+#if 0
+  if (TLI.getOperationAction(N->getOpcode(), N->getValueType(0)) == 
+      TargetLowering::Custom)
+    Res = TLI.LowerOperation(SDOperand(N, 0), DAG);
+#endif
+  
+  if (Res.Val == 0) {
+    switch (N->getOpcode()) {
+    default:
+#ifndef NDEBUG
+      cerr << "SplitOperand Op #" << OpNo << ": ";
+      N->dump(&DAG); cerr << "\n";
+#endif
+      assert(0 && "Do not know how to split this operator's operand!");
+      abort();
+#if 0
+    case ISD::STORE:
+      Res = ExpandOperand_STORE(cast<StoreSDNode>(N), OpNo);
+      break;
+#endif
+    }
+  }
+  
+  // If the result is null, the sub-method took care of registering results etc.
+  if (!Res.Val) return false;
+  
+  // If the result is N, the sub-method updated N in place.  Check to see if any
+  // operands are new, and if so, mark them.
+  if (Res.Val == N) {
+    // Mark N as new and remark N and its operands.  This allows us to correctly
+    // revisit N if it needs another step of promotion and allows us to visit
+    // any new operands to N.
+    N->setNodeId(NewNode);
+    MarkNewNodes(N);
+    return true;
+  }
+  
+  assert(Res.getValueType() == N->getValueType(0) && N->getNumValues() == 1 &&
+         "Invalid operand expansion");
+  
+  ReplaceValueWith(SDOperand(N, 0), Res);
+  return false;
+}